It is safe to say that Alan Bennett’s The History Boys is already a classic, although it premiered relatively recently, in 2004. Multiple runs in London, a successful tour to the Far East and a residency on Broadway have made it one of Bennett’s most popular plays (it was also filmed in 2006 with the original cast, led by Richard Griffiths).

It arrives at the Playhouse next week in a touring production headed by the Irish actor Gerard Murphy, who takes on the Griffiths role of Douglas Hector, long-time teacher at the fictitious Cutlers’ Grammar School in Sheffield.

Murphy told me he’s taken the part on cold: “I did not see the original production or the film, although I’m a fan of Richard and am very aware that he was wonderful in the part. But I am doing what I can to be true to Alan Bennett and to myself. I think he’s one of our greatest living writers and it’s a privilege to being doing his work.”

The director of this production is Christopher Luscombe, to whom Giles Woodforde talked at length two weeks ago in these pages about the various other theatrical outings he’s involved in.

And Luscombe is very glad he’s doing The History Boys now rather than in 20 years’ time because he’s been able to deal with Bennett directly.

“Alan is terribly accommodating. He’s very anxious not to get in the way of the production — the phrase he uses is ‘treat me like I’m a dead author’, which means we don’t have to ask his permission: he wants us to do our thing with the play.

“He does, though, like to have the casting run by him and he has the power of veto. I visited him at his house several times to have a chat and he always says ‘just ring me if there’s anything you want to ask’.”

The plot, of course, is classic Bennett territory: a group of schoolboys is being prepared for Oxbridge history entrance exams under the tutelage of Hector, whose character and foibles are central to the story.

“I suppose,” says Murphy, “it’s important to show that Hector is a passionate teacher of the old school kind — that he ‘loves’ the boys and that he is not, and never will be, in the swim of modernity.”

A tragic character? Interesting answer.

“I cannot afford as an actor playing the role to think about labels like ‘tragic’ — that is the job of the academic, I suspect!”

But Hector is truly skewered as the plot develops: the headmaster of the school has an eye on academic league tables and brings in a supply teacher, Irwin, who is very much ‘in the swim’. And then the fact that he ‘loves’ the boys takes on a darker hue.

The production team for this tour had the bright idea of asking cast members for their own experiences of school, and Luscombe’s memories are almost too perfect to be true.

“I did absolutely have a Hector figure.

“His name was Frank Miles and he was famous throughout the world of public schools. His lessons always felt like an event and you were privileged to have been part of it.”

Gerard Murphy has an even better story.

“My favourite teacher at grammar school in Northern Ireland was Brother MacFarlane. One day I was found reading a book called Two Adolescents by Alberto Moravia. The book was confiscated and as a punishment, I was beaten in front of the whole school. Later Brother MacFarlane quietly returned the book to me with the suggestion that I would enjoy it more in Italian.”

As an associate artist of the Royal Shakespeare Company, Murphy has taken on Oedipus, Dr Faustus, Oberon, Prince Hal and Petruchio.

Aged 54, he has already given his Lear, in Dublin last year. You feel that Hector will be safe in his hands.